Shuttle's delay: a chance to iron out unexpected bugs

Although the delay in launching Columbia is frustrating for astronauts Joe Engle and Richard Truly, for shuttle engineers it's all part of this spacecraft's second mission.

This mission and two to follow next year are test runs. Their main purpose is to poke and probe and exercise various capabilites to show up any problems that must be ironed out to make the shuttle Space Transportation System (STS) operational. The National Aeronautics and Space Administration (NASA) hopes to have done this by 1983.

Similarly, NASA is trying to qualify the entire STS. That means qualifying the launching facilities, tracking networks, the entire ground team, and the refurbisihing operations that turn the spacecraft around between flights, as well as the shuttle orbiter itself. Thus, the problems that delayed Columbia's launch are the sort of things NASA wants to find out at this stage.

Meanwhile, Columbia is undergoing an oil change in the three auxiliary power units that supply mechanical power to the pumps that pressurize the spacecraft's hydraulic systems. This lowers the landing gear, moves the tailrunner, and performs other such operations.

At this writing, officials were uncertain as to when to reschedule Columbia's launch. They said they very likely would know sometime Nov. 7. It would unlikely be any earlier than the following Wednesday and could be even pushed off a week beyond that.

Procedures for telling the countdown computer to modify guidelines for the pressure inside Columbia's oxygen storage bottles are being refined. The computer halted the launch at T-minus 31 seconds Nov. 4 because it hadn't gotten the word to ignore a slightly low-pressure reading.

The hydraulic systems problem tells NASA that it needs to tighten up maintenance in an area where this had been considered unnecessary. Pressure just below the maximum allowable limit in the oil lubrication lines of two of the three auxiliary power units suggests the oil is contaminated. Dwayne Weary, subsystems manager for those units, said that engineers had thought it would be unnecessary to change or clean that oil between missions. If the current inspection shows the oil to be contaminated, they will have to add maintenance procedures just as your car's engine needs a regular oil change.

When the astronauts eventually take Columbia back into orbit, the detailed testing will continue.

To begin with, the ship this time is carrying 8,795 kilograms (19,388 pounds) of payload. This allows NASA to study through all stages of a typical shuttle mission - including landing - the strains, stresses, and subtle changes in spaceship handling due to a payload.

Of course, the payload itself plays an active role. There is a set of instruments for various scientific studies of land, ocean, and atmospheric pollution. But while the data they gather will be valuable in their own right, this also is a first test of the shuttle as a platform for scientific research. All aspects of this operation will be carefully monitored, from the handling of the payload bay doors and orientation of the spacecraft to such details as how well the instruments are mated mechanically and electrically to the shuttle proper.

There is also a set of instruments to monitor the shuttle's environment. Engineers want to make sure that gases from the launching rockets don't penetrate the shuttle payload bay and contaminate any payload carried there. Also, many instruments such as telescopes or infrared sensors to be carried on operational missions are sensitive to low levels of pollutants around the spacecraft in orbit. Such pollutants could be moisture from a water dump or particles coming off the spacecraft.

This time the environmental monitoring pack will remain in the payload bay. On the next mission, which could come in January, the Canadian-supplied manipulator arm will pick up that monitoring pack and wave it around in space to sample the environment just outside the shuttle.

The arm will also be tested on this mission in a limited way. Astronaut Truly will move it and exercise it. But he won't try to grasp anything with it.

The testing and proving of the STS capabilities will continue through post-landing procedures on the ground. The astronauts will further exercise maneuvering capabilites as the craft comes in beyond what was done on the first flight. Then ground crews will try to service the shuttle and get the astronauts more quickly than before.

Ultimately, NASA hopes to refine its turnaround procedures to prepare a shuttle for relaunching in 14 days. One important step toward that goal is expected with the fourth and last test flight next year when astronauts are to land at Cape Canaveral instead of at Edwards Air Force Base on the other side of the continent.

Thus the second mission of Columbia is actually but one stage of many in developing what NASA expects to be a Space Transportation System that can operate with airline-like efficiency.